Safety device for pressure vessels



Patented Oct. 23., I

r UNITED STATES PATENT OFFICE SAFETY DEVICE FOR PRESSURE VESSELS Gwynne Raymond, Oklahoma City, Okla. Application May 17, 19%, Serial No. 487,253

(Cl. 22089) k 3 Claims.

This invention relates to safety devices for the protection of pressure vessels, systems of piping and the like apparatus wherein hazardous pressure differentials are apt to occur between the high and low pressuresides thereof. 1

Previous safety devices consist of concaveconvex diaphragms of the type illustrated in my Patent No. 1,930,960 granted October 1'7, 1933. Diaphragms of this character are usually positlonedbetween the'hig'h and low pressure sides with, thehigh pressure acting upon the concave face of the diaphragm so. that should the pres sure rise toward the danger point, the diaphragm ruptures at the predetermined pressure for I a which it wasdesigned, thereby relieving the-exsurei on the concave side of the diaphragm drops 3 below the pressure on the convex side, the diaphragm may reverse. its form and be distorted so that it is weakened to such an extent'that when the pressure again appears, the diaphragm y will burstfar below its rated rupture pressure.-

It' is the principal obiect'of the present invention to provide a safety device of this character wherein the diaphragm isnot directly subjected to pressure normally causing such distortion when the internal pressure or that acting upon the concave side drops below the external pressure or that acting upon the convex side.

In accomplishing this and other'objects of the invention as hereinafter pointed out, I have provided improved structure, the preferred form of which is illustrated in the. accompanying drawing whereimfl Fig; 1 is a perspective view, partly in section, of a safety device embodying the features of the present invention.

Fig. 2 is an enlarged fragmentary section through a portion of the safety device particularly illustrating the mounting of one of the diaphragms thereof. I Referring more in detail to thedrawing:

i designates a tank or vessel normally subject to internal pressures in excess of the external when the tank is rapidly emptied of its contents ora rapid change in temperature occurs or from any ,otherreason brought about incidental to operation of the tank. As above pointed out, this reversal of pressure effects weakening of a safety .deviceof the diaphragm type so that when the internal pressures are again established, the

safety device is apt to function below its rated pressure.

In carrying out the present invention, I have provided a safetydevice 2 of the diaphragm type I I whichis not affected by the reversal of pressure,

as nowto be described. I I

The safety device 2 includes a ring-like body member 3 having an annular wall 4 provided withbeveled ends 5 and 6 terminating in rounded ends of the body member and provide a closed chamber l1 therebetween when the diaphragms are clamped in position.

faces of the flanges are provided with annular,

shoulder-like recesses 23 having inclined faces 24 conforming to the beveled faces 5 and 6 of the body member and horizontal faces 25 spaced from and underlying the. rounded faces I and 8 of the bc dy member. The inner circumference of the clamping members thus substantially conform to the inner circumference of the body member so as to provide a substantially smooth passageway forrelieving of pressure when the diaphragms rupture as later described.

The collar portions 2| are preferably counterbored and internally threaded as at 26. The drawbolts 20 extend through openings 21 in the flanges 22 of the clamping rings and through registering openings 28 in. the reinforcing rings II and I2. ,The ends of the draw bolts project from the flanges and are provided with washers 29 and uts 30. J

The diaphragms l5 and I8 are of the type illustrated and described in the above mentioned patent and are preformed of a relatively lightweight noncorrosive, nonsparkable conductive metal that may be readily drawn to shape for providing dome shaped centra portions 31 without placing the material under intern-a1 tension that might cause thinning and weak spots which would be subject to/fractures at pressures below a predetermined pressure.

The dome portions of the diaphragms are provided with integral annular anchorage flanges. the tank is protected fromthe effects of ex- 32 which extend therefrom in rounding curves ternal pressure .xin' casefthe internal pressure 33 terminating in reversely and outwardly flarshould drop below ,th e externalpressure. Thus, ing portions 34 having laterally directed rims the criticaldi'aphragm I6 maintains its normally 3!. The curved portions 33 thus form annular 5 rated rupture pressure and will function at that groove-like seats closely engaging the rounded pressure even though the working pressure of ends of the body member and the flaring porthe tank has dropped numerous times below the tions 34 engage the bevels 5 and 6 of the body ext rnal pressure.

member, to be firmly anchored thereagainst upon What I claim and desire to secureby Letters engagement of the clamping faces 24 of the 10 Patent is:

clamping rings. The flaring portions are of suit- A sa ty pressure device including a tubular able depth so that the rims 35 overlie the faces body providing arelief passageway therethrough, of the clamping rings as shown in Fig. 2. When concavo-convex frangible .diaphragms closing the diaphragms are inposition, the convex sides endsof the tubular.- bodyzwi'thithe convex side's working pressure for which-the tank was dephrag' m thereof face inwardly of the chamber l1 and the of. said diaphragms in yfacingmelation and with concave sides face outwardly to be actedupon the'cdticave sides" adapted,to -be subjected to difby pressure of the tank and external pressure refer'ent'iat; .pressure's said ,fdiaphr'agms being spectively. adapted to' fracture-wherrthex'pressureiacting on In the illustrated instance, the safety device the concave side of one diaphragm exceeds a preis mounted upon a collar 38 which includes a 2 determinedf'maxhnum pressure for relieving said relief opening 31 in the tank I by screwing the pressure through, the relief passagewayand said collar portion of the clamping ring 19 thereon. relief pas'sageway. being? normally evacuated to A diaphragm i6 is selected, having a predeterprevent 'pre'ssures less than the bursting presmined rupture pressure above the. normal worksureacting on the concayeslde ofone-diaphragm ing pressure of the vessel but' below the safe from-dist'ortin th e' convexsidel of the other diaa a ty'pressuredevice'including a ring- Fsupporiiadapted to. encircle .the safety port '1 nd. having an annular seat, iaphragm having an annular t a said seat and arranged with e subject to pressure in said vesapted'tdjf racture when the pressure predetermined maximum, a tubular ling the convex side of the diaphragm signed. The diaphragm 5,however, is selected f; to withstand the external pressure acting on the concave side thereof since it is freed of the pres-- sure internaily'of the tank by reason of the diaphragm 16. In order that the diaphragm i6; will not be influenced by any action of the pressure acting upon the concave" side of the diaphragm 15, means is provided for establishing a 1 1,, A pressure in the chamber" l1 lower than any pressure, which may act on the concave side of the diaphragm i cdnvex dia'phragm having a flange seated on the T e va uum may be sta s i th amothenend" aid body with the convex side of the her I! through an opening 38 in the side wall of v aphra acing the convex side of the first and riga'ginggsaid flange, a frangible concavo-,-

the .body member through a pipe 3 9"threadedf :named fdiaphragm and subject to pressure exinto the ope "and aving a shut-off 'valve l0 ;tern'ally" of {the-vessel, said passageway between therein. The other en f th p pe may be conthe-diaphragm being evacuated so as to prencted with any Suitab e vacuum pumpwhere y vent fluctuation .of one diaphragm from being a desired vacuum may be drawn within the transmitted to the convex side of the other diachamber I1 after which the valve is closed to 5 phragm, a ring-like support engaging the flange maintain the vacuum. i of the last named diaphragm, and means clamp- When the internal pressure in the tankdrops ing the body. 'between the supporting rings to below the external pressure or that acting upon anchor said diaphragms.

the concave side of the diaphragm I5, the exter- 3, A safety pressure device including a support nal pressure will be comp ete y blocked from the adapted to encircle the safety port in a pressure convex side of the diaphragm i6 and any movevessel, a concave-convex diaphragm seated on ment that may be effected in the diaphragm 15 said support with the concave side subject to cannot be transmitted to the critical diaphragm pressure insaid vessel and adapted to fracture Therefore, e iaphragm I6 is not subwhen the pressure exceedsapr'edetermined maxijected to distortion but retains its normal shape mum insaid vessel, a tubular body encircling and calculated rupture pressure. When presthe convex side of the diaphragm, a diaphragm sures build up within the tank and rise above support carried atthe opposite end of the tuth pressure forwhich the diaphragm I6 is rated, bular body, a similar concave-convex frangible the diaphragm ruptures and allows release of diaphragm on the support at said opposite end pressure-before dangerous pressure is reached. with the convex side of'the diaphragm facing Release of pressure into the chamber I1 is with the convex side of the first named diaphragm S o y that diaphragm I5 is reversed and and with the concave side subject to pressure ruptured to complete the flow passageway for externally of the vessel to protect the convex relief of internal pressure in thevessel. side of the first nanied diaphragm from said If it is desired, the clamping ring 18' may be external pressure, said passageway between the provided with a pipe having the end thereof diaphragms being evacuated so as to prevent threaded into the collar portion of the ring for fluctuations that occur under nominal pressures conducting and carrying away pressure released on one diaphragm from being transmitted to the from the tank when the di'aphragms are ruptured. convex side of the other diaphragm, and means From the foregoing it is obvious that I have r retaining the diaphragm 01159161 Supporting provided a safety device wherein the diaphragm members. which is dependent upon maintaining safetywf GWYNNE RAYMOND. 

